Integrated depth sensor window lens and method

ABSTRACT

A method of making an integrated depth sensor window lens, such as for an augmented reality (AR) head set, the depth sensor window lens comprising a sensor lens and an illuminator lens separated by an opaque dam. The method uses a two-shot injection molding process, a first shot comprising an optically clear polymeric material to form the sensor lens and the illuminator lens and the second shot comprising an opaque polymeric material to form the separator of the two.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application claims priority to U.S. Provisional PatentApplication 62/809,537 entitled “Integrated Depth Sensor Window Lens andMethod” and filed Feb. 22, 2019, which is specifically incorporatedherein by reference for all that is discloses and teaches.

BACKGROUND

Augmented reality (AR) and mixed reality (MR) are technologies thatprovides an augmented real-world environment where the perception of areal-world environment (or data representing a real-world environment)is augmented or modified with computer-generated virtual data. Forexample, data representing a real-world environment may be captured inreal-time using sensory input devices, such as a camera or microphone,and augmented with computer-generated virtual data, such as virtualimages and virtual sounds. An AR or MR implementation may be used toenhance numerous applications including video game, mapping, navigation,and mobile device applications.

A head mounted display or head mounted device (HMD) is worn by a user toview the mixed imagery of virtual and real objects. An HMD uses acombination of optics and stereopsis to focus virtual imagery in theuser's field of view. Industrial design and manufacturing challengescontinue to impact HMDs, particularly as devices shrink and yet becomemore functional and complex. Device appearance also influencesconsiderations.

SUMMARY

The described technology addresses such limitations by providing ahead-mounted display or head mounted device (HMD).

A depth sensor window lens for an HMD can be made, in oneimplementation, by: injecting an optically clear polymeric material intoa first mold to form a sensor lens and an illuminator lens; injecting anopaque polymeric material into a second mold subsequent to the operationof injecting an optically clear polymeric material, the second molddefining a dam between the sensor lens and the illuminator lens andforming an as-molded part; and extracting the as-molded part from thesecond mold, the as-molded part having a front surface of the dam within10 nm of a front surface of the sensor lens and a front surface of theilluminator lens.

This summary is provided to introduce a selection of concepts in asimplified form that are further described below in the DetailedDescription. This summary is not intended to identify key features oressential features of the claimed subject matter, nor is it intended tobe used to limit the scope of the claimed subject matter.

Other implementations are also described and recited herein.

BRIEF DESCRIPTIONS OF THE DRAWINGS

FIG. 1 is a perspective view of an example head-mounted device (HMD)with a detailed perspective view of an example depth sensor window lens.

FIG. 2 is a perspective front view of an example depth sensor windowlens.

FIG. 3 is a perspective back view of an example depth sensor windowlens.

FIG. 4 is a top view of an example depth sensor window lens.

FIG. 5 is a perspective exploded view of an example depth sensor windowlens.

FIG. 6 is a flow chart showing an example process for making an exampledepth sensor window lens.

FIG. 7 is a schematic diagram of a two-shot rotary injection moldingmachine.

FIG. 8A is a perspective front view of the sensor and illuminator lensesformed by the first shot of a two-shot injection molding process; FIG.8B is a perspective back view of the sensor and illuminator lensesformed by the first shot; FIG. 8C is a perspective view of a frameformed by the second shot of a two-shot injection molding process; FIG.8D is a perspective view of the combined sensor and illuminator lensesand frame as formed by the two-shot injection molding process; FIG. 8Eis a perspective view of the combined lenses and frame after machining,resulting in the depth sensor window lens.

FIG. 9A is a photomicrograph of a back side of the depth sensor windowlens, showing the juncture of a dam and lenses; FIG. 9B is a secondphotomicrograph of the back side of the depth sensor window lens,showing the juncture of the dam and lenses; FIG. 9C is a photomicrographof the front surface of the depth sensor window lens, showing thejuncture between the dam and lenses.

DETAILED DESCRIPTIONS

A head mounted display or head mounted device (HMD) for augmentedreality (AR) and/or mixed reality (MR) uses a combination of optics andstereopsis to focus virtual imagery in the user's field of view. Thedepth sensor window lens, made by the methods disclosed herein, providesan enhanced user experience for the user using the HMD due to the depthsensor window lens and the manner in which it is constructed. Themethods presented herein provide a precise, optical-quality lens thatenhances the user's experience. This disclosure addresses both designand manufacturing sides for the HMD, as described below.

Particularly, described herein is a method of making a depth sensorwindow lens for an AR HMD or MR HMD, although the method can be used forother visual displays needing the same degree of optical preciseness.

Described herein is a method of making an optical-grade lens usingtwo-shot injection molding. One particular method described hereinincludes using dual-shot or two-shot injection molding (e.g., rotationalinjection molding) to form the lens.

In one particular implementation, this disclosure provides a method thatincludes injecting an optically clear polymeric material (e.g.,optically transparent and/or translucent) into a first mold to form asensor lens and an illuminator lens; injecting an opaque polymericmaterial into a second mold subsequent to the operation of injecting anoptically clear polymeric material, the second mold defining a dambetween the sensor lens and the illuminator lens and forming anas-molded part; and extracting the as-molded part from the second mold,the as-molded part having a front surface of the dam within 10 nm of afront surface of the sensor lens and a front surface of the illuminatorlens.

The disclosure also provides a depth sensor window lens comprising asensor lens comprising an IR transparent polymer having an RMS surfacefinish of no more than 6 nm, an illuminator lens comprising an IRtransparent polymer having an RMS surface finish of no more than 6 nm,and a dam between the sensor lens and the illuminator lens, the damcomprising an opaque polymer and having a front surface within 10 nm ofa front surface of the sensor lens and a front surface of theilluminator lens. Such a depth sensor window lens may be integrated intoa lens for an HMD.

This disclosure also provides an HMD having a visor; and a depth sensorwindow lens integrated into the visor, the depth sensor window lensincluding a sensor lens comprising an IR transparent polymer having anRMS surface finish of no more than 6 nm, an illuminator lens comprisingan IR transparent polymer having an RMS surface finish of no more than 6nm, and a dam between the sensor lens and the illuminator lens, the damcomprising an opaque polymer and having a front surface within 10 nm ofa front surface of the sensor lens and a front surface of theilluminator lens.

FIG. 1 illustrates an example HMD 100 having a visor 110 that can besupported onto a user's head by a strap 120, which may include a backsupport 122 to increase the user's comfort. The visor 110 has a viewingarea or lens 112 essentially commensurate with the user's total field ofview (TFOV) while wearing the HMD 100.

In AR and/or MR applications, the HMD 100 provides a user interface tomanage (e.g., activate, deactivate) applications in the HMD 100. Thevisor 110 includes the circuitry, processor(s), modules, electronics,etc. for the HMD 100; in some implementations, circuitry, processor(s),modules, etc., may be present in the back support 122.

In the HMD 100, the viewing area or lens 112 couples at least a portionof an optimized image to the user's focal region. Inertial, magnetic,mechanical and/or other sensors sense orientation information for theHMD and eye tracking sensors detect user eye position. A processingunit, in communication with the display, and inertial and/or othersensors and eye tracking sensors, automatically determine the totalfield of view (TFOV) of the user. The processing device then generatesand displays a first menu including a list of one or more applicationsin the TFOV. The processing device receives a user selection to activatean application from the list. The processing device further generates asecond menu including a list of one or more applications that arecurrently running in the HMD and displays the second menu in a secondregion of the TFOV. The second menu includes the application activatedby the user. The HMD 100 of FIG. 1 satisfies the user's desire of smallform factor size, a hidden sensor module, safety, working sensor angles,and industrial design needs.

For many of the applications of the HMD 100, depth sensing is paramount.

Because of this, the HMD 100 includes a time-of-flight (TOF) depthsensing sensor within the visor 110. The TOF-based depth-sensingtechnology uses specific wavelength IR light to illuminate thesurrounding mapping areas and uses an imaging sensor to capture the IRimage for depth computing. The TOF depth sensor is integrated into thevisor lens 112 and is shown in FIG. 1 behind a depth sensor window lens114. The depth sensor window lens 114 may be referred to as anintegrated depth sensor window lens when present in, and part of, thevisor lens 112.

The integrated depth sensor window lens 114 has two parts or halves, onelens 116 for the sensor and the other lens 118 for the illuminator whichtogether provide depth sensing. A sensor 140 is shown behind the lens116 and two illuminators 141, 142 are shown behind the lens 118, the twoilluminators 141, 142 having opposite polarities. Although FIG. 1 hasthe sensor lens 116 and the sensor 140 on the right side, as viewed by awearer of the HMD, and the illuminator lens 118 and the illuminators141, 142 on the left side, it is understood that these may be switched.

The sensor lens 116 and the illuminator lens 118 are held by a frame115, which in this implementation, provides a separation between thelenses 116, 118 and also encompasses the lenses 116, 118 around theirperiphery. The image sensing lens 116 and illuminator lens 118 areoptically separated to prevent stray light caused by the illuminationreflection inside the lens from disrupting proper depth sensing. In FIG.1, the sensor lens 116 and the illuminator lens 118 are separated by anopaque dam 117 that is part of the frame 115. From an industrial designand device appearance standpoint, a seamless outline is desired. Toprovide a desirable product, the HMD 100 has a compact size depth sensorwindow lens 114, with less than 5 mm distance between the lenses 116,118, and thus a width of the dam 117 of less than 5 mm. In someimplementations, this distance is less than 2 mm, in otherimplementations less than 1 mm.

The depth sensor window lens 114 is configured to allow for bothilluminations to shine-through and the sensor to collect light withoutsacrificing optical performance and device aesthetics. In accordancewith this disclosure, the window lens 114 is formed by a two-shotinjection molding process, the first shot forming the illuminator lens118 and the sensor lens 116 and the second shot forming the frame 115including the dam 117 between the illuminator lens 118 and the sensorlens 116).

FIG. 2 illustrates a depth sensor window lens 214 from a frontperspective view, the window lens 214 having a sensor lens 216 and anilluminator lens 218 held in a frame 215. The frame 215 includes a framedam 217 that seats between the sensor lens 216 and the illuminator lens218 and optically decouples the two lenses 216, 218. The dam 217 extendsfrom the front surface of the lenses 216, 218 to at least the backsurface of the lenses 216, 218; in other words, the dam 217 has athickness the same as or greater than the thickness of the lenses 216,218.

In some implementations, the thickness of the sensor lens 216 and theilluminator lens 218 is 1 mm or less. In some implementations, the widthof the dam 217 between the lenses 216, 218 is less than 5 mm, e.g., lessthan 2 mm, about 1 mm, less than 1 mm, e.g., about 0.8 mm or about 0.9mm.

In accordance with this disclosure, the depth sensor window lens 214 isan integral, single part, having the lenses 216, 218 and the frame 215formed via the same process. No adhesive, welding, bonding, mechanicalfastener, or other mechanism is used to hold or retain the lenses 216,218 with the frame 215; rather, the process of forming the lenses 216,218 and the frame 215 forms the depth sensor window lens 214 as oneintegral part.

FIG. 3 illustrates a depth sensor window lens 314 from a backperspective view, which is the orientation see by a user of an HMD whenthe window lens 314 is incorporated into the HMD. The window lens 314has a sensor lens 316 and an illuminator lens 318 held in a frame 315.The frame 315 includes a frame dam 317 that seats between the sensorlens 316 and the illuminator lens 318 and optically decouples the twolenses 316, 318. The dam 317 extends from the front surface of thelenses 316, 318 past the back surface of the lenses 316, 318. The frame315 also contacts the lens 316, 318 at and around their periphery,including the back surfaces of the lenses 316, 318 proximate theirperipheries.

Various features of the depth sensor window lens 314 and its elementsnot detailed here may be the same as or similar to details provided forother implementations described herein.

FIG. 4 is a top view of a depth sensor window lens 414 having a sensorlens 416 and an illuminator lens 418 held in a frame 415. The frame 415includes a frame dam 417 that seats between the sensor lens 416 and theilluminator lens 418 and optically decouples the two lenses 416, 418.The dam 417 extends from a front surface 426 of the sensor lens 416 toand past a back surface 436, and from a front surface 428 of theilluminator lens 418 to and past a back surface 438. Although notreadily apparent in FIG. 4, the frame 415 engaged with the lens 416, 418at the dam 417 and around the periphery of the lenses 416, 418 on theback surfaces 436, 438.

The dam 417 is substantially flush with the front surfaces 426, 428 ofthe lenses 416, 418, within no more than 10 nm, in some implementations,no more than 8 nm, or 6 nm. In FIG. 4, the front surface 426 of the lens416 meets the dam 417 at a valley 456, and the front surface 428 of thelens 418 meets the dam 417 at a valley 458. These valleys 456, 458 areno than 10 nm deep, 8 nm deep, or 6 nm deep, and are no than 10 nm wide,8 nm wide, or 6 nm wide. In some implementations, the width of the dam417, measured between the lenses 416, 418, is less than 5 mm, e.g., lessthan 2 mm, about 1 mm, less than 1 mm, e.g., about 0.8 mm or about 0.9mm.

In some implementations, the thickness of the lenses 416, 418, from thefront surface 426, 428 to the back surface 436, 438 is 1 mm or less.

Various features of the depth sensor window lens 414 and its elementsnot detailed here may be the same as or similar to details provided forother implementations described herein. It is noted that the particularconfiguration of the back side of the frame 415 is for attaching orinstalling the depth sensor window lens 414 in an HMD visor, such asvisor 110 of FIG. 1.

FIG. 5 is an exploded view of a depth sensor window lens, with a sensorlens 516 and an illuminator lens 518 removed from and separated from aframe 515, which has a dam 517 shaped and sized to seat between thelenses 516, 518 when the frame 515 and lenses 516, 518 are combined.Additionally, the frame 515 contacts the lenses 516, 518 at theirrespectively peripheries 546, 548 and on their back surfaces proximatethe peripheries 546, 548.

Various features of the depth sensor window lens, the sensor lens 516,the illuminator lens 518 and their elements not detailed here may be thesame as or similar to details provided for other implementationsdescribed herein.

As indicated above, this disclosure addresses both the design andmanufacturing perspectives for the depth sensor window lens, e.g., theintegrated depth sensor window lens.

From the design perspective, while both the sensor and the illuminatorhave their own optically clear lens, they are joined together to form asingle part with an optical isolated (e.g., opaque) barrier or dambetween the two lenses to prevent the light from leaking and reflectingto the adjacent chamber. The lenses are optically clear, IR plastic(polymeric) lenses that can pass the specific wavelength light which thedepth module operates. The opaque dam in the middle has high opaqueness(e.g., an optical density greater than 4). The combination of the threeindividual pieces (two lenses and one frame) forms a single, integralpart that has the desired characteristics: mirror polished surfacefinish for at least the lenses, the seamless joint line, the opticallyclear IR lenses and the opaque middle frame. In some implementations,both the lenses and the frame are visually black in color.

In the field of injection molding manufacturing, single operationdouble-shot injection molding has been used on many products, such askeyboard buttons. However, use of an optically graded, mirror polishsurface finish on double-shot parts, to achieve a seamless appearance,has yet to be implemented in optical devices such as HMDs. One of thechallenges is that the valley at a joint boundary or juncture during adouble-shot process can be much deeper than an optical grade mirrorpolish (e.g., <6 nm surface roughness (Ra)). Thus, the juncture isusually noticeable, which affects the aesthetic aspect of the product.If the process is not managed right, any deep valley at the juncture(e.g., greater than about 10 nm) can cause unexpected stray light fromthe ambient world to affect the depth measurement.

In accordance with this disclosure, to achieve a shallow, lessnoticeable valley (e.g., less than 10 nm, or less than 8 nm, or evenless than 6 nm deep, and optionally less than 10 nm, or 8 nm, or 6 nmwide) between the lenses and the dam, the tooling tolerance for thefirst and second shot are extremely tight, e.g., within 10 nm, so thatwhen the tool (mold) closes, material can flow through and fully fillthe juncture where the second shot meets the first shot, thus inhibitingany valley. The injection process is also precisely controlled so thesecond shot molding material can fully fill the juncture region, fromthe front surfaces of the first shot to the back surfaces, whileinhibiting the formation of voids and melting or softening of the firstshot material.

An example overall processes for producing a depth sensor window lens(which includes the two optically clear lenses having a mirrorfinish—for the sensor and the illuminator—and the frame that includes anoptically opaque dam separating the sensor lens and the illuminatorlens) includes the following steps. First, appropriate tooling (mold) isobtained for the two lenses (first shot) and the frame (second shot).The tooling is shaped and sized to tight tolerance in order to obtainthe eventual product. The tooling may be formed, e.g., of nickel,stainless steel (e.g., Stavex™ stainless steel) or a combinationthereof; the tooling may be, e.g., stainless steel with a nickelcoating. In some implementations, the tooling may have a mirror polishsurface finish. The tooling is used in a double-shot injection moldingprocess, which may be done in a cleanroom (e.g., 10K class cleanroom).The resulting piece has an RMS surface roughness of less than 6 nm. Thepiece is quality checked, and then coated with at least one protectivecoating (e.g., 10K class cleanroom) to provide a coated piece with aUV/VIS transmission of T_(max)<1% and T_(avg)<0.5% and an NIRtransmission of: T_(avg)>94% at 0 degree angle of incidence, T_(avg)>90%at 40 degree angle of incidence, T_(avg)>68% at a 70 degree angle ofincidence, T_(min)>92% at a 0 degree angle of incidence, T_(min)>88% ata 40 degree angle of incidence, and T_(min)>66% at a 70 degree angle ofincidence, as determined by a subsequent quality check. Upon approval,the piece is machined (e.g., using a Beijing Carver CNC machine, and/orin a 10K class cleanroom) to a tolerance of ±0.05 mm. After anotherquality check, which may be or include a visual cosmetic inspection, thepiece is packaged (e.g., in a plastic turnover tray) for eventualinstallation into an HMD, e.g., at the same facility or by anotherparty.

As indicated above, the process utilizes a double-shot, two-shot ordual-shot injection molding process. FIG. 6 shows a stepwise process 600for forming a depth sensor window lens using a double-shot injectionmolding method.

The process 600 includes a first injection operation 602 where the firstshot is molded in a first mold; the first mold may have a mirror qualitysurface finish. The injection operation 602 includes injecting a firstpolymeric material, e.g., IR transparent, into the first mold to formthe lenses for the illuminator and the sensor. At an opening operation604, the first mold is opened, and at least a part of the mold isremoved from the formed lenses. At a rotating operation 606, the moldedpart is rotated, e.g., on a rotary table, to the location of a secondmold. A second injection operation 608, the second mold is used formolding a second shot of polymeric material, e.g., opaque material, forforming the frame around the lenses; the second mold may have a mirrorquality surface finish. This second shot may occur within, e.g., 30seconds, 20 seconds, 15 seconds, or even 10 seconds after the firstshot. This second shot inherently adheres to the first part (lenses)during the process, so that no additional fastening or connectingmechanism is added between the parts. The first shot may or may not becompletely cured or polymerized when the second shot is injected. Inanother opening operation 610, the second mold is opened, and thetwice-molded part is removed from the second mold in a picking operation612, e.g., by a mechanical hand. At this stage, the twice-molded part,particularly the lenses formed by the first shot, have a mirror-qualityfinish, and/or an RMS surface roughness of less than 6 nm.

It is noted that the process 600, in one implementation, includes twodifferent cavities (molds) that utilize the same cores on a rotarytable. This allows a process where both the first shot and the secondshot are working simultaneously; that is, while the first shot isinjecting into the first mold, the second shot is injecting into thesecond mold. After these processes, the rotary table rotates, moving thecores in position for the next shots.

FIG. 7 illustrates an example rotary injection molding machine 700suitable for implementing the process 600. The injection molding machine700 has a rotary table 705 and a first mold 710 and a second mold 720,the first mold 710 including a first cavity 712 and a first core 714 andthe second mold 720 including a second cavity 722 and a second core 724.The first mold 710 receives the first shot of material (to form thelenses) and the second mold 720 receives the second shot of material (toform the frame). Each or either of the molds 710, 720 may have a mirrorfinish. In FIG. 7, two sets of lenses are formed via the first mold 710,and two frames are formed via the second mold 720, one frame for eachset of lenses.

A first screw 718, operably connected to an extruder, provides thematerial to the first mold 710 and a second screw 728, operablyconnected to an extruder, provides the material to the second mold 720.

The injection molding machine 700 is configured to have both the firstmold 710 and the second mold 720 to operate simultaneously; that is,both the first shot of material and the second shot of material areinjected at the same time.

In one particular implementation of the molding processes, theparameters are as follows:

Lens (1st shot) material: Trinseo Emerge PC 4310-15 IR Transparent

-   -   Color: IC1600059; Black in visual color, transparent in IR    -   Sample properties: superior flow for lens molding; good optical        properties/transmissivity; good abrasion resistance    -   Molding temperature: 305° C.

Frame (2nd shot) material: Trinseo Emerge PC 4310-22 IR Opaque

-   -   Color: IC77000367; Black in visual color and in IR    -   Sample properties: high optical isolation properties (OD-4);        high toughness and flexural strength for the snap features;        superior flow for fine features molding    -   Molding temperature: 280° C.

For both the first shot and the second shot of the polymeric material,the viscosity of the polymeric material during the injection molding isdependent on the polymeric material itself, the molding temperature, andthe mold configuration. For example, for the first shot (lenses), at amolding temperature of 300° C. the viscosity is about 350 Pa-s, at about315° C. the viscosity is about 200 Pa-s, at about 330° C. the viscosityis about 120 Pa-s, and at about 340° C. the viscosity is less than 100Pa-s. As another example, for the second shot (frame), at a moldingtemperature of 270° C. the viscosity is about 500 Pa-s, at about 280° C.the viscosity is about 400 Pa-s, at about 290° C. the viscosity is about300 Pa-s, and at about 340° C. the viscosity is about 200 Pa-s.

It is noted that polymeric materials other than polycarbonate may beused for the lens and/or the frame. The material selection should bemade taking into consideration molding capabilities, optical properties,and compatibility between the materials of the two shots.

Typically, the material for the lenses (for the sensor and illuminator)is IR transparent and optionally optically clear polycarbonate, althoughother IR transparent and optionally optically clear polymeric materialscould be used. The lens material can be any amorphous thermoplasticmaterial that is IR transparent and/or translucent, at least atwavelengths of 750 nm-1000 nm. Examples of suitable materials includepolycarbonate (PC), acrylonitrile butadiene styrene (ABS), polystyrene(PS), polyethylene (PE), polylactic acid (PLA), polymethyl methacrylate(PMMA), any of various acrylics or polyamides (e.g., “Nylon”), and anymixtures and/or blends thereof. The polymeric material may be 100%solids or may include a solvent. It is understood that adjuvants such asfillers, initiators, processing aids, pigments, etc. could be present inthe polymeric material.

The material for the frame should have good opaque properties (e.g.,OD4+), particularly for IR radiation. Because the frame is the secondshot in the molding process, the material should have an equivalent orlower molding temperature than the lens material (first shot). Thematerial also should have good bonding strength with the first shotmaterial, so that no adhesives or other fastening or bonding mechanismsare used to retain the frame to the lenses. Similar to the lenses,examples of suitable materials for the frame include polycarbonate (PC),acrylonitrile butadiene styrene (ABS), polystyrene (PS), polyethylene(PE), polylactic acid (PLA), polymethyl methacrylate (PMMA), any ofvarious acrylics or polyamides (e.g., “Nylon”), and any mixtures and/orblends thereof. The frame material may be colored any color. Thepolymeric material may be 100% solids or may include a solvent. It isunderstood that adjuvants such as fillers, initiators, processing aids,pigments, etc. could be present in the polymeric material.

FIGS. 8A through 8E show an example depth sensor window lens at variousstages in the manufacturing process. In FIGS. 8A and 8B, the result ofthe first shot is shown as a part 810, in front view (FIG. 8A) and backview (FIG. 8B); this part 810 will eventually be the lenses, and in someimplementations is formed by two discrete, unconnected parts. FIG. 8Cshows the second shot, alone, as an as-molded frame 820. However,according to the method described herein, the second shot is injecteddirected onto and around the first part 810, forming the resultingas-molded part 830 of FIG. 8D, having both the part 810 and theas-molded frame 820. The as-molded part 830 can be coated with aprotective hardcoat on either or both the front and back side. Aftermachining, trimming or other post-processing of the as-molded part 830to remove extraneous material (e.g., with a CNC machine), either beforeor after any protecting hardcoat, the final product is shown in FIG. 8Eas a depth sensor window lens 840. This depth sensor window lens 840 canthen be installed in an HMD, forming an integrated depth sensor windowlens.

An example summary of the optical requirements for the finished part(lens+frame) are provided in Table 1 and in Table 2. Table 2 providesproperties for when polycarbonate is used for the lenses (first shot).

TABLE 1 REQUIRE- PARAMETER MENT COMMENT Haze <1% more than 1% scatter isunacceptable Scratch/dig 20/10 According to MIL-13830B spec; scratchesto not exceed 20 μm width, digs not to exceed 10 μm diameter Bubbles/ 3× 0.01 mm Up to 3 bubbles/inclusion up to 10 μm inclusions in sizeSurface roughness 6 nm RMS Across entire aperture Surface error <λ/4Across entire aperture (λ = 850 nm) Cracks/chips/dust/ Nonefingerprints/ acceptable glue/dirt/stains

TABLE 2 TRANSMISSION AT PARAMETER REQUIREMENT WAVELENGTH COMMENT UV/VIStransmission T_(max) < 1% 300-800 nm For AOI* ranging from 0-(inner/outer surface) T_(avg) < 0.5% 30 degrees (unpolarized light) NIRtransmission T_(avg) > 94% 840-890 nm For AOI* ranging from 0-(inner/outer surface) T_(min) > 90% 30 degrees (unpolarized light) NIRtransmission T_(max) < 1% 930-1100 nm For AOI* ranging from 0-(inner/outer surface) T_(avg) < 0.5% 30 degrees (unpolarized light)Coatings Front surface: anti-reflecting coating + anti-scratch hardcoatBack surface: anti-reflecting coating + anti-scratch hardcoat *angle ofincidence

FIGS. 9A through 9C are photomicrographs under a high resolutionmicroscope of an example depth sensor window lens formed by adouble-shot injection molding technique according to this disclosureusing polycarbonate. FIGS. 9A and 9B show the two-shot boundary on theback side of the part near the dam. Particularly, in FIGS. 9A and 9B,two different views of a juncture of a lens 910 with a dam 917 are seen,this juncture being on the back surface of the lens 910, proximate theperiphery of the lens 910. The region labeled 999 is not a feature ofthe depth sensor window lens but is the microscope support surface.

FIG. 9C shows the double-shot boundary on the front side. Particularly,in FIG. 9C the juncture of a first lens 910A and a second lens 910B withthe dam 917 is seen as a “top-down” view along the front of the lenses910A, 910B and the dam 917, similar to the view of FIG. 4. The junctureof the first lens 910A and the dam 917 forms a first valley 950A and thejuncture of the second lens 910B, and the dam 917 forms a second valley950B. The region labeled 999 is not a feature of the depth sensor windowlens but is the microscope support surface.

As seen in FIG. 9C, even though using the two shot injection moldingmethod of this disclosure, an identifiable, very shallow valley orvalleys may exist at the juncture of the lenses and the dam. However,with an anti-reflection coating applied to the lenses and optionally tothe dam, the junctures are not noticeable by naked eyes in the finalproduct. Further, a black color to the dam and the lenses further masksthe juncture valleys.

An example method includes injecting an optically clear polymericmaterial into a first mold to form a sensor lens and an illuminatorlens, and injecting an opaque polymeric material into a second moldsubsequent to the operation of injecting an optically clear polymericmaterial, the second mold defining a dam between the sensor lens and theilluminator lens and forming an as-molded part. The method also includesextracting the as-molded part from the second mold, the as-molded parthaving a front surface of the dam within 10 nm of a front surface of thesensor lens and a front surface of the illuminator lens.

Another example method, of any preceding method, uses a two-shotinjection molding process.

Another example method, of any preceding method, is provided wherein theoptically clear polymeric material includes IR transparentpolycarbonate.

Another example method, of any preceding method, is provided wherein theopaque polymeric material includes polycarbonate. The opaque polymericmaterial may include polycarbonate having an optical density greaterthan 4.

Another example method, of any preceding method, is provided wherein theopaque polymeric material includes polycarbonate and a second polymer.

Another example method, of any preceding method, is provided wherein theopaque polymeric material is black.

Another example method, of any preceding method, is provided wherein theoptically clear polymeric material is translucent black.

Another example method, of any preceding method, is provided wherein thefront surface of the sensor lens and the front surface of theilluminator lens have an RMS surface finish of no more than 6 nm.

Another example method, of any preceding method, is provided whereineach of the first mold and the second mold have a mirror surface finish.

Another example method, of any preceding method, further includesapplying a hard coat coating to the sensor lens and the illuminatorlens.

Another example method, of any preceding method, further includestrimming the as-molded part to form a depth sensor window lens.

An example depth sensor window lens includes a sensor lens including anIR transparent polymer having an RMS surface finish of no more than 6nm, an illuminator lens including an IR transparent polymer having anRMS surface finish of no more than 6 nm, and a dam between the sensorlens and the illuminator lens. The dam includes an opaque polymer andhas a front surface within 10 nm of a front surface of the sensor lensand a front surface of the illuminator lens.

Another example depth sensor window lens, of any preceding window lens,is provided wherein the dam has a width between the lenses of 1 mm orless.

Another example depth sensor window lens, of any preceding window lens,is provided wherein the front surface of the dam is within 6 nm of thefront surface of the sensor lens and the front surface of theilluminator lens.

Another example depth sensor window lens, of any preceding window lens,is provided wherein the sensor lens and the illuminator lens include IRtransparent polycarbonate, and the dam includes polycarbonate having anoptical density greater than 4.

Another example depth sensor window lens, of any preceding window lens,further includes a frame in contact with a periphery of the sensor lensand a periphery of the illuminator lens, the frame including the dam.The frame may contact a back surface of the sensor lens proximate theperiphery and a back surface of the illuminator lens proximate theperiphery.

An example head mounted device (HMD) for augmented reality (AR) or mixedreality (MR) includes a visor lens and a depth sensor window lensintegrated into the visor lens. The depth sensor window lens includes asensor lens including an IR transparent polymer having an RMS surfacefinish of no more than 6 nm. The depth sensor window lens also includesan illuminator lens comprising an IR transparent polymer having an RMSsurface finish of no more than 6 nm. A dam is between the sensor lensand the illuminator lens, the dam including an opaque polymer and havinga front surface within 10 nm of a front surface of the sensor lens and afront surface of the illuminator lens.

Another example depth sensor window lens, of any preceding window lens,further includes a frame in contact with a periphery of the sensor lensand a periphery of the illuminator lens, the frame including the dam.

An example system includes means for injecting an optically clearpolymeric material into a first mold to form a sensor lens and anilluminator lens, and means for injecting an opaque polymeric materialinto a second mold subsequent to the operation of injecting an opticallyclear polymeric material, the second mold defining a dam between thesensor lens and the illuminator lens and forming an as-molded part. Thesystem also includes means for extracting the as-molded part from thesecond mold, the as-molded part having a front surface of the dam within10 nm of a front surface of the sensor lens and a front surface of theilluminator lens.

Another example system, of any preceding system, uses a two-shotinjection molding process.

Another example system, of any preceding system, is provided wherein theoptically clear polymeric material includes IR transparentpolycarbonate.

Another example system, of any preceding method, is provided wherein theopaque polymeric material includes polycarbonate. The opaque polymericmaterial may include polycarbonate having an optical density greaterthan 4.

Another example system, of any preceding system, is provided wherein theopaque polymeric material includes polycarbonate and a second polymer.

Another example system, of any preceding system, is provided wherein theopaque polymeric material is black.

Another example system, of any preceding system, is provided wherein theoptically clear polymeric material is translucent black.

Another example system, of any preceding system, is provided wherein thefront surface of the sensor lens and the front surface of theilluminator lens have an RMS surface finish of no more than 6 nm.

Another example system, of any preceding system, is provided whereineach of the first mold and the second mold have a mirror surface finish.

Another example system, of any preceding system, further includes ameans of applying a hard coat coating to the sensor lens and theilluminator lens.

Another example system, of any preceding system, further includes ameans of trimming the as-molded part to form a depth sensor window lens.

The above specification and examples provide a complete description ofthe process and use of example implementations of the invention. Theabove description provides specific implementations. It is to beunderstood that other implementations are contemplated and may be madewithout departing from the scope or spirit of the present disclosure.The above-detailed description, therefore, is not to be taken in alimiting sense. While the present disclosure is not so limited, anappreciation of various aspects of the disclosure will be gained througha discussion of the examples provided.

Unless otherwise indicated, all numbers expressing feature sizes,amounts, and physical properties are to be understood as being modifiedby the term “about.” Accordingly, unless indicated to the contrary, thenumerical parameters set forth are approximations that can varydepending upon the desired properties sought to be obtained by thoseskilled in the art utilizing the teachings disclosed herein.

As used herein, the singular forms “a,” “an,” and “the” encompassimplementations having plural referents, unless the content clearlydictates otherwise. As used in this specification and the appendedclaims, the term “or” is generally employed in its sense including“and/or” unless the content clearly dictates otherwise.

Spatially related terms, including but not limited to, “lower,” “upper,”“beneath,” “below,” “above,” “on top,” etc., if used herein, areutilized for ease of description to describe spatial relationships of anelement(s) to another. Such spatially related terms encompass differentorientations of the device in addition to the particular orientationsdepicted in the figures and described herein. For example, if astructure depicted in the figures is turned over or flipped over,portions previously described as below or beneath other elements wouldthen be above or over those other elements.

Since many implementations of the invention can be made withoutdeparting from the spirit and scope of the invention, the inventionresides in the claims hereinafter appended. Furthermore, structuralfeatures of the different implementations may be combined in yet anotherimplementation without departing from the recited claims.

What is claimed is:
 1. A method comprising: injecting an optically clearpolymeric material into a first mold to form a sensor lens and anilluminator lens; injecting an opaque polymeric material into a secondmold subsequent to the operation of injecting an optically clearpolymeric material, the second mold defining a dam between the sensorlens and the illuminator lens and forming an as-molded part; andextracting the as-molded part from the second mold, the as-molded parthaving a front surface of the dam within 10 nm of a front surface of thesensor lens and a front surface of the illuminator lens.
 2. The methodof claim 1, using a two-shot injection molding process.
 3. The method ofclaim 1, wherein the optically clear polymeric material comprises IRtransparent polycarbonate.
 4. The method of claim 1, wherein the opaquepolymeric material comprises polycarbonate.
 5. The method of claim 4,wherein the opaque polymeric material comprises polycarbonate having anoptical density greater than
 4. 6. The method of claim 1, wherein theopaque polymeric material comprises polycarbonate and a second polymer.7. The method of claim 1, wherein the opaque polymeric material isblack.
 8. The method of claim 1, wherein the optically clear polymericmaterial is translucent black.
 9. The method of claim 1, wherein thefront surface of the sensor lens and the front surface of theilluminator lens have an RMS surface finish of no more than 6 nm. 10.The method of claim 1, wherein each of the first mold and the secondmold have a mirror surface finish.
 11. The method of claim 1, furthercomprising: applying a hard coat coating to the sensor lens and theilluminator lens.
 12. The method of claim 1, further comprising:trimming the as-molded part to form a depth sensor window lens.
 13. Adepth sensor window lens comprising: a sensor lens comprising an IRtransparent polymer having an RMS surface finish of no more than 6 nm;an illuminator lens comprising an IR transparent polymer having an RMSsurface finish of no more than 6 nm; and a dam between the sensor lensand the illuminator lens, the dam comprising an opaque polymer andhaving a front surface within 10 nm of a front surface of the sensorlens and a front surface of the illuminator lens.
 14. The depth sensorwindow lens of claim 13, wherein the dam has a width between the lensesof 1 mm or less.
 15. The depth sensor window lens of claim 13, whereinthe front surface of the dam is within 6 nm of the front surface of thesensor lens and the front surface of the illuminator lens.
 16. The depthsensor window lens of claim 13, wherein the sensor lens and theilluminator lens include IR transparent polycarbonate, and the damincludes polycarbonate having an optical density greater than
 4. 17. Thedepth sensor window lens of claim 13 further comprising: a frame incontact with a periphery of the sensor lens and a periphery of theilluminator lens, the frame including the dam.
 18. The depth sensorwindow lens of claim 17, wherein the frame further contacts a backsurface of the sensor lens proximate the periphery and a back surface ofthe illuminator lens proximate the periphery.
 19. A head mounted device(HMD) for augmented reality (AR) comprising: a visor lens; and a depthsensor window lens integrated into the visor lens, the depth sensorwindow lens comprising: a sensor lens comprising an IR transparentpolymer having an RMS surface finish of no more than 6 nm; anilluminator lens comprising an IR transparent polymer having an RMSsurface finish of no more than 6 nm; and a dam between the sensor lensand the illuminator lens, the dam comprising an opaque polymer andhaving a front surface within 10 nm of a front surface of the sensorlens and a front surface of the illuminator lens.
 20. The HMD of claim19, wherein the depth sensor window lens further comprising a frame incontact with a periphery of the sensor lens and a periphery of theilluminator lens, the frame including the dam.